0000000000925496
AUTHOR
G. Spadaro
Radiation processing for synthesis of structural materials
Mechanical properties of blends of low density polyethylene with isotactic polypropylene II. effect of mixing temperature and rate
Abstract The effects of mixing temperature and rate on tensile properties of some blends of low density polyethylene with isotactic polypropylene have been studied. Results, with those presented previously on the effect of mixing time, indicate significant effects of mixing parameters and suggest the need to find an “optimum mixing procedure” for each kind of blend.
Chronic rhinosinusitis with nasal polyps impact in severe asthma patients: Evidences from the Severe Asthma Network Italy (SANI) registry
Abstract Background The clinical and laboratory features of patients enrolled in the Severe Asthma Network in Italy (SANI) registry, a web-based observatory collecting demographic, clinical, functional and inflammatory data of patients with severe asthma were evaluated, with a special emphasis to chronic rhinosinusitis with nasal polyposis (CRSwNP). Methods For each eligible patients the following information has been collected: demographic data, clinical features, asthma control in the previous month according to the GINA (Global INitiative for Asthma) Guidelines and standardized questionnaires, concomitant regular and on demand treatments and inflammatory markers. Results 695 patients wit…
Radiation engineered nanogels as platforms for medical diagnostics and therapeutic nanodevices
A scalable, single step, synthetic approach for the manufacture of biocompatible, functionalized microgels and nanogels has been developed. Pulsed EB irradiation of PVP aqueous solutions, at relatively low energies per pulse and doses within the sterilization dose range, has led to a variety of ‘as-born’ sterile, functional nanostructures that exhibit a combination of favourable properties which make them suitable as biomedical nanocarriers. Reactive functional groups have been generated by graft copolymerization of functional acrylic monomers. These groups can be used to attach fluorescent probes to the NPs, to bioconjugate ligands of specific cell receptors and to incorporate therapeutics…
Study of methyl methacrylate polymerization in the presence of rubbers
Grafting of poly(methylmethacrylate) onto various unsaturated rubbers is described. The grafting is achieved through thermally initiated methylmethacrylate in-situ polymerization. The main features of the polymerization process, i.e. conversion vs. time, grafting to rubber and gel percentage, have been investigated. The chemical structure of the rubber influences the process: rubber with pendant unsaturations gives rise to higher level of grafting.
Carbon fibre composite materials produced by gamma radiation induced curing of epoxy resins
It is well known that ionizing radiation can initiate polymerization of suitable monomers for many applications. In this work an epoxy dlfunctional monomer has been used as matrix of a carbon fibre composite in order to produce materials through gamma radiation, for aerospace and advanced automotive applications. Radiation curing has been performed at different absorbed doses and, as comparison, also thermal curing of the same monomer formulations has been done. Furthermore some Irradiated samples have been also subjected to a post Irradiation thermal curing in order to complete the polymerization reactions. The properties of the cured materials have been studied by moisture absorption isot…
E-beam curing of epoxy based blends in order to produce high performance composites
In this work, blends of a difunctional epoxy monomer and a thermoplastic toughening agent are E-beam irradiated at two different dose rates and two different total absorbed doses. The influence of the processing conditions on the thermal properties and on the morphology of the obtained matrices has been investigated. In particular, it is shown how the increase of the dose rate causes an increase of the temperature during irradiation, thus inducing a simultaneous thermal and radiation curing. On the contrary, at low-dose rate the system mainly undergoes to radiation curing, thus making the cured material very sensible to a post-irradiation thermal treatment with a significant improvement of …
Reply to: Kow CS et al. Are severe asthma patients at higher risk of developing severe outcomes from COVID-19?
Studies of network organization and dynamics of e-beam crosslinked PVPs: From macro to nano
Abstract In this work the influence of poly(N-vinyl pyrrolidone) (PVP) concentration in water on the organization and dynamics of the corresponding macro-/nanogel networks has been systematically investigated. Irradiation has been performed at the same irradiation dose (within the sterilization dose range) and dose rate. In the selected irradiation conditions, the transition between macroscopic gelation and micro-/nanogels formation is observed just below the critical overlap concentration (∼1 wt%), whereas the net prevalence of intra-molecular over inter-molecular crosslinking occurs at a lower polymer concentration (below 0.25 wt%). Dynamic–mechanical spectroscopy has been applied as a cl…
Biocompatible polyaniline nanocomposites build a soft interface between biology and opto-electronics
Mode I fracture toughness behaviour of epoxy resincarbon fiber composites cured by ionising radiation
In this work Mode I fracture toughness behavior of Electron Beam cured unidirectional CFRP laminates is investigated by means of standardized Double Cantilever Beam (DCB) tests. A matrix system, comprising a DGEBA epoxy monomer and a typical initiator of cationic polymerization, was used and panel samples assembled by hand lay-up. Curing was achieved by 20 to 40 minutes irradiation on a pulsed 10 MeV Electron Beam accelerator. One batch of resin was also mixed with 10 phr of a PES thermoplastic monomer in order to enhance the matrix toughness. The influence of fibre-matrix adhesion, matrix toughening and matrix crosslinking density on the mode I delamination behavior have been investigated …
Epoxy resin-thermoplastic blends cured by ionising radiation. Structure/properties relationships
Radiation curing of an epoxy resin based blend is carried out in order to produce polymer matrices for high-performance composites. A suitable choice of both curing process and formulation parameters allows to irradiate at about 60°C. Moreover hydrothermal ageing is performed on cured materials and their properties have been evaluated
Stress relaxation of a polyisobutylene under large strains
Stress relaxation data after single and double elongational strain “steps” were collected on a commercial polyisobutylene, Oppanol B 50. Analogously to other cases a separability of deformation and time effects was observed over an extended time region for the relaxation after single “steps”. Moreover, by comparing the results after double with those after single steps, it was noted that any rheological equation of integral type having a rigorously constant memory function is not able to describe accurately the full body of results presented here. On the other hand the data were favorably compared with the predictions of a model proposed earlier.